1. Field of the Invention
The present invention generally relates to a package device, particularly to indicate to a package device with electromagnetic interference shield.
2. Description of the Prior Art
In recently, the electrical technology is developed rapidly, and the electronic equipment is used for widely application. Because of the electromagnetic interference is generated from the electronic equipment and the restraint is generated from the environment of the electronic equipment, the electromagnetic compatibility for the electronic equipment is an important issue to consider. The objective of the shielding structure is that preventing the performance of other electronic devices is to be reduced, or the damage to the inside electronic device.
In general, the electromagnetic/radio frequency interference would be caused by the package device is that the interaction between the every electronic devices located on the package device. For example, the noise capacitance and inductance would be influenced the package device when the work current passed through the conductive wirings, or the signal passed through the grounded line, or the mutual inductance is caused between the conductive wirings.
FIG. 1 shows the package device that utilizes the metal sheet to be an electromagnet interference shield. The package device includes a substrate which consisted of an insulating layer 110/a metal sheet 112/an insulating layer 114, wherein the metal sheet 112 is a shielding structure for reducing the electromagnetic/radio frequency interference, and a heat dissipation apparatus which is attached to another insulating layer 114. The conventional separating apparatus 116 consisted of a plurality of power devices, which is electrically coupled with the printed circuit board 122 through the pin 120. Thus, the electromagnetic/radio frequency is generated from the package device that can be discharged or eliminated through the printed circuit board 122 to the grounded (not shown).
The heat is generated from the conventional separating apparatus 116 in the package device. The heat is dissipated via the heat dissipation apparatus 118 for the package device. However, the heat dissipating capability is not good for the insulating layer 114. The heat is generated from the power devices 116 that would be dissipated through the insulating layer 110/metal sheet 112/insulating layer 114 to the heat dissipation apparatus 118 to affect the stability of the package device. Even the electromagnetic/radio frequency interference of the package device can be discharged by external connecting to the printed circuit board 122 and the grounded (not shown in figure).
FIG. 2 shows another conventional separating apparatus structure for the package device. According to the above illustration of FIG. 1, the capability of the substrate is not good for heat dissipating when the constructed material is insulating layer 110/metal sheet 112/insulating layer 114. Therefore, the difference between the FIG. 1 and FIG. 2 is that the shielding structure is a single insulating layer 110. The insulating layer 110 is electrically coupled with the power device 116, and another side of insulating layer 110 is attached to the heat dissipation apparatus 118. Similarly, the power device 116 is electrically coupled with the printed circuit board 122 through the pin 120. Another difference between FIG. 1 and FIG. 2 is that the package device is electrically coupled with the shielding structure via the conductor. Herein, the shielding structure is a single layer which consisted of the metal layer 126 and the printed circuit board 128, or a multilayer structure which consisted of alternated a plurality of metal layers 126 and a plurality of printed circuit boards 128. The single layer or multilayer of shielding structure is used for discharging the electromagnetic/radio frequency from the printed circuit board 128 through the power device 116, the shielding structure to the conductor 124 to form a shielding path of discharging the electromagnetic/radio frequency. According to the above discussion would be obtained the heat dissipating path for the package device, but the fabricating of the package device is still difficult and the cost would be increased.